diff --git a/android/java/org/chromium/chrome/browser/crypto_wallet/fragments/PortfolioFragment.java b/android/java/org/chromium/chrome/browser/crypto_wallet/fragments/PortfolioFragment.java
index f8de69288c6..4cd6aabf224 100644
--- a/android/java/org/chromium/chrome/browser/crypto_wallet/fragments/PortfolioFragment.java
+++ b/android/java/org/chromium/chrome/browser/crypto_wallet/fragments/PortfolioFragment.java
@@ -220,10 +220,10 @@ public class PortfolioFragment
         List<WalletListItemModel> walletListItemModelList = new ArrayList<>();
         String tokensPath = ERCTokenRegistryFactory.getInstance().getTokensIconsLocation();
         for (ErcToken userAsset : userAssets) {
-            String currentAssetSymbol = userAsset.symbol.toLowerCase();
-            Double fiatBalance = perTokenFiatSum.getOrDefault(currentAssetSymbol, 0.0d);
+            String currentAssetSymbol = userAsset.symbol.toLowerCase(Locale.getDefault());
+            Double fiatBalance = Utils.getOrDefault(perTokenFiatSum, currentAssetSymbol, 0.0d);
             String fiatBalanceString = String.format(Locale.getDefault(), "$%,.2f", fiatBalance);
-            Double cryptoBalance = perTokenCryptoSum.getOrDefault(currentAssetSymbol, 0.0d);
+            Double cryptoBalance = Utils.getOrDefault(perTokenCryptoSum, currentAssetSymbol, 0.0d);
             String cryptoBalanceString =
                     String.format(Locale.getDefault(), "%.4f %s", cryptoBalance, userAsset.symbol);
 
@@ -286,7 +286,8 @@ public class PortfolioFragment
         String chainId = Utils.getNetworkConst(getActivity(), chainName);
         portfolioHelper.setChainId(chainId);
         portfolioHelper.calculateBalances(() -> {
-            final String fiatSumString = String.format(Locale.getDefault(), "$%,.2f", portfolioHelper.getTotalFiatSum());
+            final String fiatSumString =
+                    String.format(Locale.getDefault(), "$%,.2f", portfolioHelper.getTotalFiatSum());
             PostTask.runOrPostTask(UiThreadTaskTraits.DEFAULT, () -> {
                 mBalance.setText(fiatSumString);
                 mBalance.invalidate();
diff --git a/android/java/org/chromium/chrome/browser/crypto_wallet/util/PortfolioHelper.java b/android/java/org/chromium/chrome/browser/crypto_wallet/util/PortfolioHelper.java
index 0151ab7c88f..722b85adf1e 100644
--- a/android/java/org/chromium/chrome/browser/crypto_wallet/util/PortfolioHelper.java
+++ b/android/java/org/chromium/chrome/browser/crypto_wallet/util/PortfolioHelper.java
@@ -17,9 +17,11 @@ import org.chromium.brave_wallet.mojom.ErcToken;
 import org.chromium.brave_wallet.mojom.EthJsonRpcController;
 import org.chromium.brave_wallet.mojom.KeyringController;
 import org.chromium.chrome.browser.crypto_wallet.util.AsyncUtils;
+import org.chromium.chrome.browser.crypto_wallet.util.Utils;
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Locale;
 
 public class PortfolioHelper {
     private static String TAG = "PortfolioHelper";
@@ -81,7 +83,8 @@ public class PortfolioHelper {
             ArrayList<AsyncUtils.GetPriceResponseContext> pricesContexts =
                     new ArrayList<AsyncUtils.GetPriceResponseContext>();
             for (ErcToken userAsset : mUserAssets) {
-                String[] fromAssets = new String[] {userAsset.symbol.toLowerCase()};
+                String[] fromAssets =
+                        new String[] {userAsset.symbol.toLowerCase(Locale.getDefault())};
                 String[] toAssets = new String[] {"usd"};
 
                 AsyncUtils.GetPriceResponseContext priceContext =
@@ -110,7 +113,8 @@ public class PortfolioHelper {
                         return;
                     }
                     tokenToUsdRatios.put(
-                            priceContext.prices[0].fromAsset.toLowerCase(), usdPerToken);
+                            priceContext.prices[0].fromAsset.toLowerCase(Locale.getDefault()),
+                            usdPerToken);
                 }
 
                 mKeyringController.getDefaultKeyringInfo(keyringInfo -> {
@@ -150,9 +154,10 @@ public class PortfolioHelper {
 
                         balancesMultiResponse.setWhenAllCompletedAction(() -> {
                             for (AsyncUtils.GetBalanceResponseBaseContext context : contexts) {
-                                String currentAssetSymbol = context.userAsset.symbol.toLowerCase();
-                                Double usdPerThisToken =
-                                        tokenToUsdRatios.getOrDefault(currentAssetSymbol, 0.0d);
+                                String currentAssetSymbol =
+                                        context.userAsset.symbol.toLowerCase(Locale.getDefault());
+                                Double usdPerThisToken = Utils.getOrDefault(
+                                        tokenToUsdRatios, currentAssetSymbol, 0.0d);
 
                                 Double thisBalanceCryptoPart =
                                         context.success ? fromHexWei(context.balance) : 0.0d;
@@ -160,13 +165,14 @@ public class PortfolioHelper {
                                 Double thisBalanceFiatPart =
                                         usdPerThisToken * thisBalanceCryptoPart;
 
-                                Double prevThisTokenCryptoSum =
-                                        mPerTokenCryptoSum.getOrDefault(currentAssetSymbol, 0.0d);
+                                Double prevThisTokenCryptoSum = Utils.getOrDefault(
+                                        mPerTokenCryptoSum, currentAssetSymbol, 0.0d);
+
                                 mPerTokenCryptoSum.put(currentAssetSymbol,
                                         prevThisTokenCryptoSum + thisBalanceCryptoPart);
 
-                                Double prevThisTokenFiatSum =
-                                        mPerTokenFiatSum.getOrDefault(currentAssetSymbol, 0.0d);
+                                Double prevThisTokenFiatSum = Utils.getOrDefault(
+                                        mPerTokenFiatSum, currentAssetSymbol, 0.0d);
                                 mPerTokenFiatSum.put(currentAssetSymbol,
                                         prevThisTokenFiatSum + thisBalanceFiatPart);
 
diff --git a/android/java/org/chromium/chrome/browser/crypto_wallet/util/Utils.java b/android/java/org/chromium/chrome/browser/crypto_wallet/util/Utils.java
index f16df1d0755..3f3e5190d5c 100644
--- a/android/java/org/chromium/chrome/browser/crypto_wallet/util/Utils.java
+++ b/android/java/org/chromium/chrome/browser/crypto_wallet/util/Utils.java
@@ -602,4 +602,13 @@ public class Utils {
             return source;
         }
     }
+
+    public static Double getOrDefault(
+            HashMap<String, Double> map, String key, Double defaultValue) {
+        // Can't use java.util.HashMap#getOrDefault with API level 21
+        if (map.containsKey(key)) {
+            return map.get(key);
+        }
+        return defaultValue;
+    }
 }